Universal Lighting Source Controller with Integral Power Metering

ABSTRACT

A universal lighting source controller including integral power metering for use with substantially all light source types including fluorescent, incandescent, magnetic low voltage, electronic low voltage, light emitting diode (“LED”), high density discharge (“HID”), neon, and cold cathode. The lighting source controller includes a line voltage dimming circuit that can control the intensity of light sources in a lighting circuit and measures the actual amount of power consumed by the light sources. The line voltage dimming circuit includes a triac circuit for controlling this intensity and current and voltage detection circuits for measuring the power consumption. The lighting source controller can also include low voltage dimming circuits to provide a control signal to light sources having electronic or magnetic dimming ballasts to set the intensity of these light sources.

TECHNICAL FIELD

The invention relates generally to lighting source controllers, and morespecifically to universal lighting source controllers having integralpower metering.

BACKGROUND

A lighting source controller is an electronic device used to control oneor more light sources, such as a fluorescent, incandescent, or lightemitting diode (LED) lamp. A lighting source controller activates alight source based on various conditions including occupancy, desireduse and time of day. A lighting source controller also controls theintensity of the light source to provide a dimming effect. One of thebenefits of lighting control is that dimmed light sources consume lessenergy than lighting at full load. For this reason, lighting control hasbeen used in various control schemes to reduce demand during peak energydemand times or simply to conserve energy on an ongoing basis.

Some programs supporting energy conservation, such as the Leader inEnergy and Environmental Design (LEED) certification, require validationand measurement of actual energy usage to prove the lighting controlsystems are realizing reduced energy consumption. To meet thisrequirement, a separate energy metering system is typically employed togather the required data. These systems are expensive as they requirethe design, installation, and maintenance of a second system.

Therefore, a need currently exists in the art for a lighting sourcecontroller that both controls and measures energy usage of light sourceswithout the need for a separate energy metering system.

Many commercial and industrial buildings utilize more than one type oflight source. For example, some buildings employ incandescent,fluorescent, and LED lamps, all in the same building. A conventionallighting source controller typically needs a separate control circuit orcontrol card for each type of light source. This leads to higher costsincurred during the design of the lighting source controller and highmaintenance costs for the lighting system. It also requires keeping morespare controller cards readily available, in case one of the controllercards needs replacement. Accordingly, a need also exists in the art fora lighting source controller circuit or controller card capable ofcontrolling multiple types of light sources.

SUMMARY

The universal lighting source controller can include integral powermetering capability for use with substantially all common types of lightsources, including fluorescent, incandescent, magnetic low voltage,electronic low voltage, light emitting diode (LED), high-intensitydischarge (HID), neon, and cold cathode.

The lighting source controller typically includes line voltage dimmingcards for controlling and measuring power usage for a lighting circuithaving one or more light sources. For example, a lighting control panelcan include a single controller for the panel with multiple line voltagedimming cards, each line voltage dimming card controlling and meteringenergy usage for a lighting circuit with one or more lights. Thecontroller can receive configuration information and control informationfor each of the dimming cards and communicate this information to thedimming cards. The controller can receive the configuration informationfrom a user interface having a display and input devices. The controllercan also receive control information from the user interface or fromanother device connected to the controller via a network. For example,the controller can be connected to a building management system via anetwork, such as Ethernet or RS485. This building management system cansend commands to the controller to turn lighting circuits on or offand/or set dimming levels for the light sources in the lightingcircuits.

The line voltage dimming cards can include a dimming circuit capable ofcontrolling the intensity level for lights connected to the dimmingcard. This dimming circuit is universal and can be used with most commonlight sources, including fluorescent, incandescent, magnetic lowvoltage, electronic low voltage, LED, HID, neon, and cold cathode. Theline voltage dimming card also can include voltage detection circuitryand current detection circuitry. A microprocessor in the line voltagedimming card can receive current and voltage measurements from thecurrent sensor and voltage detection circuitry respectively andcalculate the power usage of the lighting circuit controlled by the linevoltage dimming card. The microprocessor can then communicate this powerusage information to the controller, which in turn can output the powerusage information on the user interface.

The lighting source controller can also include low voltage dimmingcards capable of providing a dimming control signal to light sourceshaving electronic or magnetic dimming ballasts. For these light sources,a line voltage dimming card can be used to provide power for the lightsources and to measure the power usage of the light sources, while a lowvoltage dimming card can be used to provide the dimming control. The lowvoltage dimming card can provide common ballast dimming control signals,including 0-10 VDC, 1-10 VDC, and digital dimming control signals.

The controller can receive power usage information from each of the linevoltage dimming cards and communicate this information to the userinterface or to a remote computer for display. The controller can alsocalculate additional information for display to a user, such as theamount of power being used for each phase of a three phase system andthe total amount of power consumed for all circuits connected to thecontroller.

These and other aspects, features and embodiments of the invention willbecome apparent to a person of ordinary skill in the art uponconsideration of the following detailed description of illustratedembodiments exemplifying the best mode for carrying out the invention aspresently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the exemplary embodiments of thepresent invention and the advantages thereof, reference is now made tothe following description, in conjunction with the accompanying figuresbriefly described as follows.

FIG. 1 is a block diagram depicting a universal lighting sourcecontroller having integral power metering in accordance with oneexemplary embodiment of the present invention.

FIG. 2 is a block diagram depicting a line voltage dimming card inaccordance with one exemplary embodiment of the present invention.

FIG. 3 is an electrical circuit diagram depicting a zero cross circuitand a voltage detection circuit of a line voltage dimming card inaccordance with one exemplary embodiment of the present invention.

FIGS. 4A and 4B are electrical circuit diagrams depicting voltagedetection circuits of a line voltage dimming card in accordance with oneexemplary embodiment of the present invention.

FIG. 5 is an electrical circuit diagram depicting an analog amplifiercircuit of a line voltage dimming card in accordance with one exemplaryembodiment of the present invention.

FIG. 6 is an electrical circuit diagram depicting a microprocessorcircuit of a line voltage dimming card in accordance with one exemplaryembodiment of the present invention.

FIG. 7 is an electrical circuit diagram depicting a surge protectioncircuit, a relay, a relay drive circuit, and a dimmer circuit of a linevoltage dimming card in accordance with one exemplary embodiment of thepresent invention.

FIG. 8 is an electrical circuit diagram depicting communication circuitsand optical isolation circuits of a line voltage dimming card inaccordance with one exemplary embodiment of the present invention.

FIG. 9 is an electrical circuit diagram depicting a power supply circuitof a line voltage dimming card in accordance with one exemplaryembodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following description of exemplary embodiments refers to theattached drawings, in which like numerals indicate like elementsthroughout the figures. FIG. 1 is a block diagram depicting an exemplaryuniversal lighting source controller 100 having integral power meteringin accordance with one exemplary embodiment of the present invention.The lighting source controller 100 controls and meters power usage forsubstantially all types of light sources, including fluorescent,incandescent, magnetic low voltage, electronic low voltage, lightemitting diode (LED), high-intensity discharge (HID), neon, and coldcathode.

In this exemplary embodiment, the lighting source controller 100includes a panel controller 105 for controlling and metering the powerusage of multiple lighting circuits from a single lighting panel (notshown). The panel controller 105 is in electrical communication with auser interface 110, a digital communications module 115, one or moreline voltage dimming cards 130 and one or more low voltage dimming cards140. The panel controller 105 also receives power from a power supply120 and provides supply power to each of the line voltage dimming cards130 and each of the low voltage dimming cards 140.

The panel controller 105 receives input from users and providesinformation to users via the user interface 110. The user interface 110can be presented on a variety of displays including a liquid crystaldisplay (LCD), a computer monitor, or a touchscreen. In certainexemplary embodiments, a user configures the panel controller 105, theline voltage dimming cards 130, and the low voltage dimming cards 140using input devices, such as a pointing device or keypad coupled to theuser interface 110. The user interface 110 communicates thisconfiguration information to and receives information from the panelcontroller 105 via various interfaces, including, for example, Ethernet,Universal Serial Bus (USB), and RS485.

The digital communications module 115 provides for electricalcommunication between the panel controller 105 and various other systemsor computers via a network. For example, in one exemplary embodiment,the digital communications module 115 includes an Ethernet interfacethat provides control of light sources from a building management systemand provides diagnostics and monitoring capabilities from a remotecomputer. Other non-limiting examples of communication protocols thatcan be provided by the digital communications module 115 include RS485and DMX512 (e.g. control by entertainment systems) serial communicationprotocols.

The lighting source controller 100 includes any number of line voltagedimming cards 130 and low voltage dimming cards 140. Each line voltagedimming card 130 controls and meters the power usage of a lightingcircuit having one or more light sources. The line voltage dimming cards130 are universal and are used with various types of light sources,including fluorescent, incandescent, magnetic low voltage, electroniclow voltage, LED, HID, neon, and cold cathode. For example, the sameline voltage dimming card 130 can be removed from a lighting circuit ofincandescent lights and installed in a lighting circuit of fluorescentlights without any hardware modifications.

The line voltage dimming cards 130 receive configuration and controlinformation from the panel controller 105 and provide the panelcontroller 105 with the power usage information for its lightingcircuit. In one exemplary embodiment, the configuration informationvaries based on the lighting supply power and desired control scheme andincludes parameters such as a high power limit, low power limit, asetting for turning the lighting source off when input power is belowthe low power limit or stay on at low limit, and a setting for transientresponse between the high and low power limits, such as linear, squarelaw, or switched only. The configuration information also includes asetting for scaling the transient response based on the high and lowpower limits. In one exemplary embodiment, these parameters are receivedfrom a user via the user interface 110. Alternatively, the configurationinformation is received from a remote computer via the digitalcommunications module 115.

A user programs the panel controller 105 to communicate with the linevoltage dimming cards 130 to activate a lighting circuit and control theintensity or dimming of the light sources in the circuit based onvarious factors, including time of day, occupation of area, desired use,and amount of lighting present in the area. Alternatively, the panelcontroller 105 receives control information from an outside source, suchas a building management system or an entertainment system.

As discussed in more detail below with reference to FIG. 2, each linevoltage dimming card 130 includes a microprocessor for controlling thelight sources for its respective lighting circuit. The microprocessoralso receives power usage information for the lighting circuit providedby one or more voltage detection circuits and a current detectioncircuit. This power usage information is communicated to the panelcontroller 105 and outputted at the user interface 110 and optionally ata remote computer via the digital communications module 115.

The low voltage dimming cards 140 provide a dimming control signal tolight sources having an electronic or magnetic dimming ballast. Examplesof light sources having electronic dimming ballasts include analogfluorescent (2, 3, or 4-wire), LED, and HID dimmable loads. Typically,these electronic dimming ballasts control the intensity level of a lightsource based on an analog voltage or current range, such as a 0-10 VDCinput signal. Additionally, some electronic dimming ballasts control theintensity level of the light source based on a digital signal. The lowvoltage dimming cards 140 provide either an analog or digital dimmingcontrol signal to the light sources in a lighting circuit.

Similar to the line voltage dimming cards 130, the low voltage dimmingcards 140 receive configuration and control information from the panelcontroller 105. The configuration information for the low voltagedimming cards 140 varies based on the type of ballast and control schemeand includes parameters such as a low voltage high end limit (e.g. 10VDC), a low voltage low end limit (e.g. 0 VDC), a setting forcoordinating the low voltage limit and power switching (e.g. alwaysenergized or turn off below low end limit), and a setting for thedirection of the low voltage control (i.e. proportional or inverse).Additionally, in certain exemplary embodiments, the configurationinformation also includes a setting for transient response between thelow voltage limits, such as linear, square law, or switched only, and asetting for scaling the transient response according to the high end andlow end voltage limits.

A user programs the panel controller 105 to communicate with the lowvoltage dimming cards 140 to control the intensity or dimming of thelight sources in the circuit based on various factors, including time ofday, occupation of area, desired use of the area, and amount of lightingpresent in the area. Alternatively, the low voltage dimming cards 140receive control information from an outside source, such as a buildingmanagement system or an entertainment system as discussed above. In oneexemplary embodiment, the low voltage dimming cards output a dimmingcontrol signal, such as 0-10 VDC, to a lighting circuit based on thedesired dimming level.

The exemplary lighting source controller 100 includes a correspondingline voltage dimming card 130 for each low voltage dimming card 140 usedto control light sources having electronic or magnetic dimming ballasts.The corresponding line voltage dimming card 130 provides power for andmeasures power usage of the light sources, while the low voltage dimingcard 140 provides a dimming control signal for adjusting the intensityof the light sources.

FIG. 2 is a block diagram depicting a line voltage dimming card 130 inaccordance with one exemplary embodiment of the present invention. Thisexemplary line voltage dimming card 130 includes a microprocessor 205and circuitry for activating, dimming, and measuring power usage of alighting circuit having one or more light sources. The circuits of theline voltage dimming card 130 are discussed below with reference to FIG.2 and an exemplary circuit diagram for each circuit is also discussedbelow with reference to FIGS. 3-9. It should be noted that these circuitdiagrams are exemplary and can be modified without departing from thescope and spirit of the invention. It should also be noted that thevalues for the components in each of the circuit diagrams are alsoexemplary and can be modified and in some cases, the components can beremoved or other components added without departing from the scope orspirit of the invention.

Referring to FIGS. 1 and 2, the microprocessor 205 receives power fromthe panel controller 105 via a transformer 215 and a power supply 217.The transformer 215 adjusts the voltage level of the input power and thepower supply 217 converts the input alternating current (AC) power intodirect current (DC) power and provides a steady DC voltage to themicroprocessor 205.

The microprocessor 205 also receives configuration and controlinformation from the panel controller 105 as described above withreference to FIG. 1. In this exemplary embodiment, the panel controller105 communicates this information to the microprocessor 205 via a serialcommunications circuit 212, although many other communication protocolsare possible as would be known to one or ordinary skill in the arthaving the benefit of this disclosure. The microprocessor 205 alsoutilizes this serial communications circuit 212 to send the panelcontroller 105 information including power usage information for thelighting circuit that the line control dimming card 130 is controlling.The serial communications circuit 212 and the microprocessor 205 areelectrically isolated from the panel controller 105 by an opticalisolation circuit 210.

The line voltage dimming control card 130 receives power for itslighting circuit from a hot power line 221 and a neutral power line 222and outputs power onto three separate power lines, a live power line280, a switched power line 285 and a dimmed power line 290 depending onthe configuration of the lighting circuit. For example, if light dimmingis not desired, the line voltage dimming card 130 is used to switch thelight sources on and off. In this example, the lighting circuit isconnected to the switched power line 285. If dimming is desired, thelighting circuit is connected to the dimmed power line 290.Additionally, the live voltage power line 280 is provided for anemergency non-switched lighting connection.

The line voltage dimming card 130 includes a surge protection circuit225 for diverting or suppressing a spike in input voltage. In oneexemplary embodiment, the surge protection circuit 225 is positionednear the entry point of the input voltage to protect other circuits inthe line voltage dimming card 130. Various types of surge protectioncircuits 225 can be used with the line voltage dimming card 130,including metal oxide varistor circuits and suppression diode circuits.

The line voltage dimming card 130 also includes a zero cross circuit 230for detecting transitions between positive and negative voltage levelsof the input AC voltage. At each transition, the zero cross circuit 230provides a short electrical pulse to the microprocessor 205. This seriesof pulses resembles a square wave signal which is used by themicroprocessor 205 to time the energizing and de-energizing of the lightsources in a dimming application.

A current sensor 235 and an analog amplifier 237 are provided with theline voltage dimming card 130 to measure the current flow through theline voltage dimming card 130 and thus, through the lighting circuit itcontrols. This current measurement is taken along the hot power line 221and is provided to the microprocessor 205.

This exemplary line voltage dimming card 130 also includes threeseparate voltage detection circuits 240, 250, 260. The voltage detectioncircuit 240 measures the voltage level across the live voltage point 280and the neutral power line 222. The voltage detection circuit 250measures the switched output voltage level across the switched point 285and the neutral power line 222 downstream from a relay 247. The voltagedetection circuit 260 measures the dimmed voltage level across thedimmed point 290 and the neutral power line 222. In one exemplaryembodiment, each voltage detection circuit 240, 250, 260 provides themicroprocessor 205 with its respective voltage measurement.

The microprocessor 205 determines the amount of power that its lightingcircuit is consuming using the current measurement provided by thecurrent sensor 235 and a voltage measurement from one of the voltagedetection circuits 240, 250, 260 depending on the configuration orapplication of the line voltage dimming card 130. For example, if theline voltage dimming card 130 is used in a dimming application, themicroprocessor 205 uses the voltage measurement from the voltagedetection circuit 260. In an alternative exemplary embodiment when theline voltage dimming card 130 is used in a switched (non-dimming)application, the voltage measurement from the voltage detection circuit250 is used. Additionally, in emergency lighting applications, thevoltage measurement from the voltage detection circuit 240 is used. Themicroprocessor 205 communicates this power calculation to the panelcontroller 105 for display at the user interface 110 or at a remotecomputer via the digital communications module 115.

The line voltage dimming card 130 includes a relay 247 for passing orblocking electrical power along the hot power line 221 to the lightsources of the lighting circuit. The microprocessor 205 activates therelay 247 to energize the lighting loads by sending a control signal toa relay drive 245, which in turn energizes a coil in the relay 247.Although a relay 247 is utilized in this exemplary embodiment, othersuitable switching devices can be used as would be known by one ofordinary skill in the art having the benefit of the present disclosure.

The line voltage dimming card 130 also includes a dimming circuit havinga dimmer 257, a dimmer drive 255, and an inductor 265. In one exemplaryembodiment, for light sources that do not have an electronic or magneticdimming ballast, the microprocessor 205 sends electrical signals to thedimmer drive 255, which in turn, controls the dimmer to provide adimming level to light sources based on control information receivedfrom the panel controller 105. As discussed in more detail below withreference to FIG. 7, the dimmer 257 includes a triac that is activatedand deactivated at high frequencies to turn the light sources on and offat a high frequency. This reduces the total amount of energy deliveredto the light sources and therefore, reduces the intensity of the light.This dimming level is adjusted by changing the frequency of theactivation of the triac in the dimmer 257. In one exemplary embodiment,the timing of the activation and deactivation of the triac issynchronized with the zero cross signal by the microprocessor 205.

FIG. 3 is an electrical circuit diagram depicting an exemplary zerocross circuit 230 and an exemplary voltage detection circuit 240 of aline voltage dimming card 130 in accordance with the exemplaryembodiment of FIG. 2. An operational amplifier (“op-amp”) IC1A receivesAC voltage across the hot 221 and neutral 222 lines of a lightingcircuit and provides a scaled AC signal to the zero cross circuit 230and the voltage detection circuit 240. In this exemplary embodiment, theop-amp IC1A and its associated circuitry works to scale the input ACsignal to an output range of 0-5 VAC. A reference voltage REF_V of 2.5VAC is provided at the non-inverting input of the op-amp IC1A to providea bias voltage at the midrange of the scaled output range.

The zero cross circuit 230 converts the AC signal to a square-wavesignal PROC_SQ with peaks corresponding to transitions of the AC signalthrough zero volts. This square wave signal PROC_SQ is transferred to aninput of the microprocessor 205 for use in timing the activation anddeactivation of light sources in a dimming application. This exemplaryzero cross circuit 230 includes an op-amp IC1B, two inverting Schmitttriggers IC2A, IC2B connected in series at the output of the op-ampIC1B, and associated resistors and capacitors. Exemplary values for thecomponents of the zero-cross circuit 230 and for components associatedwith op-amp IC1A are listed below in Table 1.

TABLE 1 Exemplary Component Values for the Zero Cross Circuit 230 andComponents Associated with Op-Amp IC1A Circuit Component Value R1 4.7 kΩR2 990 kΩ R3 990 kΩ R4 4.7 kΩ R5 100 kΩ R6 1 MΩ R7 10 kΩ

The voltage detection circuit 240 scales the AC signal received from theop-amp IC1A and provides this scaled signal PROC_LIVE to themicroprocessor 205. The microprocessor 205 can then compare this scaledsignal PROC_LIVE to a reference voltage to calculate the actual voltagebetween the live output power line 280 and the neutral power line 222.This exemplary voltage detection circuit 240 includes an op-amp IC1D,and associated resistors and capacitors. The voltage detection circuit240 also includes a network of diodes and capacitors at the output ofthe op-amp IC1D for protecting the microprocessor 205 from voltageranges above or below the scaled range of 0-5 VAC. Exemplary values forthe components of the voltage detection circuit 240 are listed below inTable 2.

TABLE 2 Exemplary Component Values for the Voltage Detection Circuit 240Circuit Component Value R8 39 kΩ R9 82 kΩ R10 1 kΩ R11 100 kΩ C1 1 nF C21 nF C3 100 nF

FIGS. 4A and 4B, collectively FIG. 4, are electrical circuit diagramsdepicting exemplary voltage detection circuits 250, 260 of a linevoltage dimming card 130 in accordance with the exemplary embodiment ofFIG. 2. Referring to FIG. 4A, the voltage detection circuit 250 scalesthe AC signal received across the switched output power line 285 and theneutral power line 222 and provides this scaled signal PROC_SWITCHED tothe microprocessor 205. The microprocessor 205 compares this scaledsignal PROC_SWITCHED to a reference voltage to determine the actualvoltage between the switched output power line 285 and the neutral powerline 222. This exemplary voltage detection circuit 250 includes anop-amp IC3A, and associated resistors and capacitors. The voltagedetection circuit 250 also includes a network of diodes and capacitorsat the output of the op-amp IC3A for protecting the microprocessor 205from voltage ranges above or below the scaled range of 0-5 VAC.Exemplary values for the components of the voltage detection circuit 250are listed below in Table 3.

TABLE 3 Exemplary Component Values for the Voltage Detection Circuit 250Circuit Component Value R1 4.7 kΩ R2 990 kΩ R3 990 kΩ R4 1 kΩ R5 4.7 kΩC1 100 nF

Referring to FIG. 4B, the exemplary voltage detection circuit 260 scalesthe AC signal received across the dimmed output power line 290 and theneutral power line 222 and provides this scaled signal PROC_DIMMED tothe microprocessor 205. The microprocessor 205 compares this scaledsignal PROC_DIMMED to a reference voltage to calculate the actualvoltage between the dimmed output power line 290 and the neutral powerline 222. This exemplary voltage detection circuit 260 includes anop-amp IC3B, and associated resistors and capacitors. The voltagedetection circuit 260 also includes a network of diodes and capacitorsat the output of the op-amp IC3B for protecting the microprocessor 205from voltage ranges above or below the scaled range of 0-5 VAC.Exemplary values for the components of the voltage detection circuit 260are listed below in Table 4.

TABLE 4 Exemplary Component Values for the Voltage Detection Circuit 260Circuit Component Value R6 4.7 kΩ R7 990 kΩ R8 990 kΩ R9 1 kΩ R10 4.7 kΩC2 100 nF

FIG. 5 is an electrical circuit diagram depicting an exemplary analogamplifier circuit 237 of a line voltage dimming card 130 in accordancewith the exemplary embodiment of FIG. 2. This exemplary analog amplifiercircuit 237 includes an op-amp IC3C which scales a voltage measurementtaken across a current sensing resistor R44 (See FIG. 7). This voltagemeasurement is scaled by the op-amp IC3C and this scaled signal PROC_IMis transmitted to the microprocessor 205. The microprocessor 205compares the scaled signal PROC_IM to a reference voltage to determinethe current flowing through the resistor R44 and thus through thelighting circuit that the line voltage dimming card 130 controls.Exemplary values for the components of the analog amplifier circuit 237are listed below in Table 5.

TABLE 5 Exemplary Component Values for the Analog Amplifier Circuit 237Circuit Component Value R1 10 kΩ R2 150 kΩ R3 1 kΩ R4 150 kΩ R5 10 kΩ C1100 nF

FIG. 6 is an electrical circuit diagram depicting an exemplarymicroprocessor 205 circuit of a line voltage dimming card 130 inaccordance with the exemplary embodiment of FIG. 2. In one exemplaryembodiment, the microprocessor 205 includes 16 pins for sending orreceiving electrical signals. A description of the signal at each pin ofthe microprocessor 205 is described below in Table 6. This exemplarymicroprocessor 205 circuit includes a light emitting diode (LED) LD1, aclock circuit 605, and associated resistors and capacitors. This clockcircuit 605 employs a crystal oscillator X1 to provide a reference clocksignal to the microprocessor 205. Exemplary values for the components ofthe microprocessor circuit 205 are listed below in Table 7.

TABLE 6 Microprocessor 205 Input/Output Pins Pin Number Description 1Status indication. 2 Receives voltage measurement signal PROC_DIMMEDfrom the voltage detection circuit 260. 3 Receives voltage measurementsignal PROC_LIVE from the voltage detection circuit 240. 4 0 V input. 5+5 V input. 6 Receives square-wave output signal PROC_SC from the zerocross circuit 230. 7 Not used. 8 Receives clock input signal fromoscillator X1. 9 Receives clock input signal from oscillator X1. 10Outputs a communication signal to the serial communications circuit 212.11 Receives a communication signal from the serial communicationscircuit 212. 12 Outputs signal to operate the relay 247. 13 Not used. 14Receives voltage measurement signal PROC_IM from the analog amplifiercircuit 237. 15 Receives voltage measurement signal PROC_SWITCHED fromthe voltage detection circuit 250. 16 Sends dimming control signal tothe dimmer drive circuit 255.

TABLE 7 Exemplary Component Values for the Microprocessor 205 CircuitCircuit Component Value R1 330 Ω R2 4.7 MΩ R3 10 kΩ C1 22 pF C2 22 pF

FIG. 7 is an electrical circuit diagram depicting examples of a surgeprotection circuit 225, a relay 247, a relay drive circuit 245, a dimmerdrive circuit 255, and a triac dimmer 257 of a line voltage dimming card130 in accordance with the exemplary embodiment of FIG. 2. The hot powerline 221 and the neutral power line are connected to the line voltagedimming card 130 at connectors CON1 and CON2 respectively. The outputpower lines 280, 285, and 290 are connected to connector CON3 to receivepower for a light source.

The surge protection circuit 225 includes a capacitor C9 and a varistorV1. The varistor V1 acts to divert any voltage surges present along thehot line 221 in order to protect the circuitry in the line voltagedimming card 130.

The relay drive circuit 245 includes a field effect transistor (FET) Q2for controlling the relay 247. The relay drive circuit 245 receives acontrol signal PROC_RLDR from the microprocessor 205 and opens or closesthe relay 247 based on this control signal PROC_RLDR. The control signalPROC_RLDR is applied to the base 1 of the FET Q2 which allows currentflow through a channel between points 2 and 3 of the FET Q2 when thePROC_RLDR signal is above a threshold voltage. This flow of currentdrives a coil in relay 247 to close. In one exemplary embodiment,without this flow of current, the relay 247 remains open.

The dimmer drive circuit 255 includes an optoisolator triac driver IC8,two resistors R5, R7, and a capacitor C2. The triac driver IC8 receivesa dimmer controller signal OPTO_TRIAC from the microprocessor 205. Basedon the dimmer control signal OPTO_TRIAC, the triac driver IC8 energizesthe dimmer 257 to allow current to flow from the switched output powerline 285 through the dimmer 257, through an inductor 265, and to thedimmed output power line 290 at CON3. As the triac dimmer 257 and theinductor 265 can be large devices, in a panel embodiment, these devices257, 265 can be mounted external from the line dimming voltage card 130.Exemplary values for the components of the surge protection circuit 225,the relay drive circuit 245, and the dimmer drive circuit 255 are listedbelow in Table 8.

TABLE 8 Exemplary Component Values for the Surge Protection Circuit 225,the Relay Drive Circuit 255, and the Dimmer Drive Circuit 255 CircuitComponent Value R1 1 MΩ R2 (thermistor) Variable proportional totemperature R3 1 MΩ R4 1 MΩ R5 (thermistor) Variable proportional totemperature R6 (thermistor) Variable proportional to temperature R7(thermistor) Variable proportional to temperature C1 1 μF C2 100 nF

FIG. 8 is an electrical circuit diagram depicting exemplary serialcommunication circuits 212-1, 212-2 and exemplary optical isolationcircuits 210-1, 210-2 of a line voltage dimming card 130 in accordancewith the exemplary embodiment of FIG. 2. The exemplary serialcommunication circuits 212-1 and 212-2 provide serial communicationsbetween the microprocessor 205 and the panel controller 105.

The serial communication circuit 212-1 receives a serial communicationsignal TX_OC at connector CON1 and transfers the signal TX_OC to theoptical isolation circuit 210-1, which in turn transfers arepresentative signal PROC_RX to the microprocessor 205. The opticalisolation circuit 210-1 includes an optocoupler IC6 which provideselectrical isolation between the panel controller 105 and themicroprocessor 205 for the serial communication signals PROC_RX andTX_OC. The serial communications circuit 212-1 and the optical isolationcircuit 210-1 includes two capacitors C20, C40 and three resistors R52,R54, R63.

The serial communication circuit 212-2 receives a serial communicationsignal PROC_TX from the microprocessor 205 and transfers the signalPROC_TX to the optical isolation circuit 210-2 which in turn transfers arepresentative signal TX_OC to the panel controller 105. The opticalisolation circuit 210-2 includes an optocoupler IC7 which provideselectrical isolation between the panel controller 105 and themicroprocessor 205 for the serial communication signals PROC_TX andTX_OC. The serial communications circuit 212-2 and optical isolationcircuit includes a capacitor C21 and three resistors R55, R61, R62.Exemplary values for the components of the serial communication circuits212-1, 212-1 and the optical isolation circuits 210-1, 210-2 are listedbelow in Table 9.

TABLE 9 Exemplary Component Values for the Serial Communication Circuits212-1, 212-2, and the Optical Isolation Circuits 210-1 and 210-2 CircuitComponent Value R1 (thermistor) Variable proportional to temperature R2(thermistor) Variable proportional to temperature R3 3.3 kΩ R4(thermistor) Variable proportional to temperature R5 (thermistor)Variable proportional to temperature R6 (thermistor) Variableproportional to temperature C1 100 nF C2 100 nF C3 47 μF

FIG. 9 is an electrical circuit diagram depicting examples of atransformer 215 and a power supply circuit 217 of a line voltage dimmingcard 130 in accordance with the exemplary embodiment of FIG. 2. In thisexemplary embodiment, the transformer 215 receives AC power from thepanel controller 105 (See FIG. 1) and steps the input voltage down to anappropriate voltage level for the power supply circuit 217. The powersupply circuit 217 receives the stepped down voltage from thetransformer 215 and employs a voltage regulator IC5 to provide a steadyDC voltage to the microprocessor 205. This exemplary power supplycircuit 217 includes a rectifier circuit having four diodes D9, D10,D11, D12 connected across the secondary winding of the transformer 215.This rectifier circuit converts the AC voltage received on the secondarywindings of the transformer 215 into a DC voltage. The power supplycircuit 217 also includes associated inductors, resistors, capacitors,and a diode D8. Exemplary values for the components of the power supplycircuit 217 are listed below in Table 10.

TABLE 10 Exemplary Component Values for the Power Supply Circuit 217Circuit Component Value C1 100 nF C2 47 μF C3 100 nF C4 47 μF C5 100 nFL1 22 μH L2 22 μH

Although specific embodiments of the invention have been described abovein detail, the description is merely for purposes of illustration. Itshould be appreciated, therefore, that many aspects of the inventionwere described above by way of example only and are not intended asrequired or essential elements of the invention unless explicitly statedotherwise. Various modifications of, and equivalent steps correspondingto, the disclosed aspects of the exemplary embodiments, in addition tothose described above, can be made by a person of ordinary skill in theart, having the benefit of this disclosure, without departing from thespirit and scope of the invention defined in the following claims, thescope of which is to be accorded the broadest interpretation so as toencompass such modifications and equivalent structures.

1. A lighting control system, comprising: a lighting control circuitoperable to receive a control signal comprising a command to energize alight source and allow electrical energy to flow to the light source inresponse to the command; and a controller communicably coupled to thelighting control circuit, the controller operable to transmit thecontrol signal to the control circuit, wherein the lighting controlcircuit is electrically coupled to the light source, and wherein thelighting control circuit is operable for use with at least two offluorescent, incandescent, magnetic low voltage, electronic low voltage,light emitting diode (LED), high intensity discharge (HID), neon, andcold cathode light sources.
 2. The lighting control system of claim 1,wherein the lighting control circuit comprises a microprocessor operableto receive the control signal and transmit an electrical signal allowingthe flow of electrical energy to the light source in response to thecommand.
 3. The lighting control system of claim 1, wherein the controlsignal further comprises an intensity setting for the light source. 4.The lighting control system of claim 3, wherein the lighting controlcircuit adjusts the intensity level of the light source by sequentiallyallowing and blocking the flow of electrical energy to the light sourceat a frequency.
 5. The lighting control system of claim 4, wherein thecontrol circuit comprises a triac operable to sequentially allow andblock the flow of electrical energy to the light source at thefrequency.
 6. The lighting control system of claim 1, wherein thelighting control circuit further comprises a power metering circuit,wherein the power metering circuit measures an amount of electricalenergy used by the light source.
 7. The lighting control system of claim6, wherein the power metering circuit comprises: at least one voltagedetection circuit; and a current measurement circuit.
 8. The lightingcontrol system of claim 7, further comprising a user interfacecommunicably coupled to the controller, wherein the controller transmitsa representation of the amount of electrical energy used by the lightsource to the user interface for outputting to a user.
 9. The lightingcontrol system of claim 1, wherein the light source comprises anelectronic dimming ballast.
 10. The lighting control system of claim 9,further comprising a low voltage dimming circuit communicably coupled tothe electronic dimming ballast and operable to transmit a dimming levelsignal to the electronic dimming ballast, wherein the command comprisesan intensity setting for the light source and wherein the dimming levelsignal corresponds to the intensity setting.
 11. The lighting controlsystem of claim 10, wherein the dimming level signal comprises avariable analog voltage level.
 12. The lighting control system of claim10, wherein the dimming level signal comprises a digital signal.
 13. Alighting circuit control card for use with a plurality of types oflighting sources, comprising: a control circuit, electrically coupled toat least one light source, the control circuit operable to receive acontrol signal comprising an indication that the at least one lightsource should be energized and operable to permit electrical energy toflow to the at least one light source in response to the indication; anda power metering circuit operable to determine an amount of electricalpower consumed by the at least one light source.
 14. The lightingcircuit control card of claim 13, wherein the plurality of types oflighting sources comprise at least two of fluorescent, incandescent,magnetic low voltage, electronic low voltage, light emitting diode(“LED”), high density discharge (“HID”), neon, and cold cathode lightsources.
 15. The lighting circuit control card of claim 13, wherein thepower metering circuit comprises: at least one voltage detectioncircuit; and a current detection circuit.
 16. The lighting circuitcontrol card of claim 13, wherein the control signal further comprises adesired intensity level and wherein the control circuit adjusts anintensity level of the at least one light source based on the desiredintensity level.
 17. The lighting circuit control card of claim 16,wherein the control circuit adjusts the intensity level of the at leastone light source by sequentially allowing and blocking the flow ofelectrical energy to the at least one lighting source.
 18. The lightingcircuit control card of claim 17, wherein the control circuit furthercomprises a triac, wherein the triac sequentially allows and blocks theflow of electrical energy to the at least one light source at afrequency.
 19. A method for controlling a light source, the methodcomprising the steps of: receiving a control signal at a lightingcontrol circuit, the control signal comprising a command to energize thelight source and a desired intensity level for the light source; inresponse to receiving the control signal, allowing, by the lightingcontrol circuit, electrical energy to flow to the light source; andmeasuring, by the lighting control circuit, an amount of electricalenergy used by the light source, wherein the lighting control circuit isoperable for use with at least two of fluorescent, incandescent,magnetic low voltage, electronic low voltage, light emitting diode(“LED”), high density discharge (“HID”), neon, and cold cathode lightsources.
 20. The method of claim 19, wherein the step of allowingelectrical energy to flow to the light source comprises sequentiallyallowing and blocking the flow of electrical energy to the light sourceat a frequency corresponding to the desired intensity level.
 21. Themethod of claim 20, wherein the lighting control circuit comprises amicroprocessor and a triac and wherein the triac receives a signal fromthe microprocessor and in response to the signal, the trial allowselectrical energy to flow to the light source for a period of timecorresponding to the frequency.
 22. The method of claim 19, furthercomprising the step of transmitting a representation of the amount ofelectrical energy used by the light source to a user interface foroutputting to a user.
 23. The method of claim 19, further comprising thestep of receiving the control signal at a panel controller from a sourceexternal to the panel controller and the lighting control circuit,wherein the control signal is received from the panel controller. 24.The method of claim 23, wherein the source external to the panelcontroller and the lighting source comprises a building managementsystem.
 25. The method of claim 19, further comprising the step ofreceiving configuration information for the lighting control circuit.26. The method of claim 25, wherein the configuration informationcomprises a high power limit and a low power limit for the lightingsource.
 27. A lighting system, comprising: a lighting controlleroperable to send control signals to line voltage dimming cards; one ormore line voltage dimming cards communicably coupled to the lightingcontroller, each line voltage dimming card comprising: a controlcircuit, electrically coupled to a lighting circuit comprising at leastone light source, the control circuit operable to receive a controlsignal comprising an indication that the at least one light sourceshould be energized and a desired intensity level for the at least onelight source, the control circuit further operable to permit electricalenergy to flow to the at least one light source in response to theindication and control an intensity level of the at least one lightsource in response to the desired intensity level; and a power meteringcircuit operable to determine an amount of electrical power consumed bythe at least one light source in the lighting circuit; and a userinterface communicably coupled to the lighting controller and operableto receive configuration information for the panel controller and theone or more line voltage dimming cards and further operable to output arepresentation of the amount of electrical power consumed by the atleast one light source from the lighting controller, wherein each of theline voltage dimming cards is operable for use with at least two offluorescent, incandescent, magnetic low voltage, electronic low voltage,light emitting diode (“LED”), high density discharge (“HID”), neon, andcold cathode light sources.
 28. The lighting system of claim 27, whereinthe lighting controller is further operable to receive control signalsfrom a controller via a network.
 29. The lighting system of claim 27,further comprising one or more low voltage dimming cards communicablycoupled to the lighting controller, each line voltage dimming cardoperable to transmit a dimming control signal corresponding to thedesired intensity level to a light source having an electronic dimmingballast.
 30. The lighting system of claim 27, wherein the controlcircuit controls the intensity level of the at least one light source byenergizing and de-energizing the at least one light source at afrequency corresponding to the desired intensity level.
 31. The lightingsystem of claim 30, wherein the control circuit comprises a zero crosscircuit for timing the energizing and de-energizing of the at least onelight source.
 32. The lighting system of claim 27, wherein each of theline voltage dimming cards is operable for use with each of fluorescent,incandescent, and LED light sources without modification to any hardwareof the line voltage dimming card.